Using a Crown Royal bag is nothing new. There have been plenty of people using them well before his suggestion. Personally, I think they suck as a bottle cover because they don't provide grip. Furthermore, they end up getting trashed after a while from just the day to day rigors of playing paintball. I'd consider a Crown Royal bag more of trophy bottle cover that has it's place in a display case.

As mentioned before the nxe covers should work and possibly some of the newer empire ones. If you want the end caps then the exalt and ninja will suffice.